How well can an elephant's womb support an animal of a different species? Even human babies born to human mothers are in danger if something as simple as the mother's Rh factor is different than the baby's. Surely implanting an animal of one species into a completely different species will run into problems with rejection?

Are they taking any precautions against the probability that the genome contains viral components just as ours does? If they cannot prove beforehand that no virus will start replicating from the Wolly Mammoth genome once they activate it, they should not be allowed to proceed.